With the highly increased operating speed of the electronic elements in the currently available electronic products, more heat is generated by the electronic elements during operation thereof. The generated heat must be timely removed from the electronic products, lest it should adversely affect the stable operation of a central processing unit (CPU) of the electronic products. In other words, it is very important to adequately dissipate the heat generated by heat-generating electronic elements.
Heat sink is one of the most frequently devices for dissipating heat generated by electronic elements. In the early stage, a heat sink is usually integrally formed by way of aluminum extrusion, and includes a base and a plurality of radiating fins extended from one side of the base. When using this type of heat sink to dissipate heat, the base of the heat sink is tightly attached to a heat-generating electronic element, and a cooling fan is further mounted on the heat sink as an auxiliary means to help dissipate the heat from the heat sink.
However, since the amount of heat generated by the electronic elements quickly increased in recently years, the conventional heat sink can hardly meet the current requirement for heat dissipation. Therefore, heat sinks with increased heat dissipation area have been developed to provide upgraded heat dissipation ability. However, heat sinks with increased heat dissipation area inevitably have increased weight and volume to occupy largely increased space, which obviously has adverse influence on the development of compact electronic products.
Therefore, heat pipe is also employed in the electronic industry as a heat transfer element. The heat pipe is extended through a set of radiating fins and a low boiling point working fluid is filled in the heat pipe. The working fluid is vaporized in the heat pipe at a vaporizing end thereof in contact with a heat-generating electronic element, and the vapor-phase working fluid flows from the vaporizing end to an opposite condensing end of the heat pipe extended through the radiating fins, so that the heat generated by the electronic element is transferred to the radiating fins. A cooling fan is also used to produce airflow for carrying the heat away from the radiating fins to achieve the purpose of removing the heat generated by the electronic element.
In manufacturing the heat pipe, a type of metal powder is filled in a hollow pipe. The metal powder is sintered to form a wick structure on an inner wall surface of the hollow pipe. Thereafter, the pipe is vacuumed and filled with a working fluid before being sealed. And, to meet the demands for low-profile electronic devices, the heat pipe is usually further processed to form a thin heat pipe.
To form the thin heat pipe, first sinter the filled metal powder and then press the heat pipe into a flat configuration. Thereafter, after filling the working fluid, the heat pipe is sealed. Alternatively, the hollow pipe of the heat pipe can be pressed into a flat configuration before the filled metal powder is sintered. However, in the latter case, since the flattened hollow pipe defines a very narrow chamber therein, which not only causes difficulty in filling the metal powder into the hollow pipe, but also results in an extremely narrow vapor channel in the heat pipe to thereby have adverse influence on the vapor-liquid circulation in the heat pipe.
In brief, the conventional heat pipe manufacturing methods have the following disadvantages: (1) uneasy to form a thin heat pipe; (2) tending to damage the wick structure in the heat pipe; and (3) requiring relatively high manufacturing cost.